Apparatus for joining substrates together

ABSTRACT

An apparatus is provided for joining together at least two substrates, each of which has an inner hole. The apparatus has a pin that is adapted to the inner holes of the substrates. The pin is provided with at least two noses that are movable radially relative to the pin. The noses have linear outer surfaces upon which the edges of the inner holes of the substrates can glide downwardly during movement of the noses toward the pin.

BACKGROUND OF THE INVENTION

The present invention relates to an apparatus for joining together atleast two substrates, each of which has an inner hole, with theapparatus having a pin that is adapted to the inner holes of thesubstrates.

Many data carriers, such as DVD's, are generally comprised of twosubstrates that are glued together and that for the gluing are joinedtogether in a centered manner. In so doing, generally a first substratethat is provided with an adhesive coating is placed upon a planarsupport and subsequently a second substrate is moved over the firstsubstrate by means of a handling apparatus and hence the substrates arebrought together. In this connection, the handling apparatus must notonly be in a position to precisely orient these substrates relative toone another, but also to uniformly press the substrates together.However, such a handling apparatus is very complicated and expensive,and is susceptible to disruptions, which leads to irregularities duringthe joining together and adversely affects the functioning of the datacarrier and can even make it unusable.

U.S. Pat. No. 5,888,433 discloses an apparatus of the aforementionedtype for joining two substrates together. The apparatus provided with anexpandable centering boss that is comprised of three individual parts.The centering boss is introduced into the central hole of a substratethat is comprised of two glued-together substrate halves, and the bossis subsequently radially expanded. Due to the expansion, a centering ofthe two substrate halves results, after which they are glued together.This subsequent centering has a danger that the substrate halves can bedamaged, since the force applied to the substrate halves must berelatively high in order to move the substrates relative to one anotherafter the gluing.

Proceeding from the above-described apparatus, it is an object of thepresent invention to provide a simple and economical apparatus forjoining substrates together, with such apparatus enabling a reliable andprecise joining together with a low reject rate.

SUMMARY OF THE INVENTION

Pursuant to the present invention, with an apparatus for joiningtogether at least two substrates, each of which has an inner hole, andwhich apparatus has a pin that is adapted to the inner holes of thesubstrates, this object is realized in that the pin has at least twonoses that are movable radially relative to the pin, wherein the edgesof the inner holes of the substrates glide downwardly on the straight orlinear outer surfaces of the noses during movement of the noses towardthe pin. The pin makes it possible during the joining together for thesubstrates to be guided precisely centrally and parallel to one another.In particular, due to the linear outer surfaces of the noses, thesubstrates are held such that their faces are parallel to one another,and the linear outer surfaces, during the joining together, provide aconstant movement sequence. Due to the use of the pin, the requirementsmade of a handling apparatus can be significantly reduced, so that thecosts associated therewith are eliminated.

Pursuant to a particularly preferred specific embodiment of theinvention, prior to the joining together, the noses keep the substratesspaced apart, so that they are placed upon the pin and can subsequentlybe transported into a joining station in which they are joined together.The pin is advantageously a centering pin, that at least in the lowerregion has an outer periphery that corresponds to the inner periphery ofthe inner holes of the substrates in order to precisely align thesubstrates relative to one another.

For a particularly simple and economical embodiment of the invention,the noses are pivotably mounted on the centering pin. The noses areadvantageously biased outwardly by at least one biasing unit in order toachieve a controlled joining together of the substrates. In thisconnection, the biasing unit is preferably provided with at least onespring.

Pursuant to one specific embodiment of the invention, the noses aremovable toward the pin by exerting pressure upon the substrates, so thatthe substrates can be joined together in a controlled manner by a simpleexertion of pressure.

Pursuant to an alternative specific embodiment of the invention, anactuating element that radially moves the noses is provided and cancontrol the movement of the noses. For this purpose, the noses arepreferably embodied as lever arms in order to enable a simple actuationthereof. The actuating element is advantageously introducible betweenthe noses and has a conical configuration in order to enable a uniformmovement of the noses in a simple manner. For a good gliding movementbetween the noses and the actuating element, the ends of the noses areadvantageously rounded off.

Pursuant to a further specific embodiment of the invention, the biasingof the noses can be varied in order to enable a controlled gliding ofthe substrates along the outer surfaces of the noses. Advantageously, aconical or tapered element disposed in the pin is provided that ismovable counter to a biasing. In this connection the tapered element ispreferably movable against a spring.

In order to provide a controllable biasing of the noses, a biasingelement is preferably provided between the tapered element and thenoses. The outwardly directed biasing of the noses is in this connectionpreferably variable via a movement of the tapered element.

BRIEF DESCRIPTION OF THE DRAWING

Further features, advantages and details of the invention will beexplained subsequently with the aid of preferred specific embodimentswith reference to the figures, in which:

FIG. 1 is a schematic cross-sectional view through a centering pin ofthe present invention prior to the joining together of two substrates;

FIG. 2 is a schematic cross-sectional view of the centering pin of FIG.1 during the joining together of the substrates;

FIG. 3 is a schematic cross-sectional view of the centering pin and asubstrate handling apparatus for the removal of the substrates from thepin;

FIG. 4 shows a processing station for the joining together of twosubstrates, which station contains a centering pin of the presentinvention and in particular in an opened position;

FIG. 5 shows a view similar to that of FIG. 4, whereby the processingstation is shown in a closed position prior to the joining together oftwo substrates;

FIG. 6 shows a similar view to that of FIG. 4, whereby the processingstation is shown during the joining together of two substrates;

FIG. 7 shows a view similar to that of FIG. 4 of an alternativeprocessing station for the joining together of two substrates.

DESCRIPTION OF PREFERRED EMBODIMENTS

FIGS. 1 to 3 show a first embodiment of a centering and holding pin 1for receiving substrates 2,3. The pin is accommodated in anon-illustrated receiving means that defines a support for thesubstrates 2,3. A joining station, in which the pin can be inserted, isshown, for example, in the patent application belonging to thisapplicant and filed on the same day as the present application andhaving the title “Apparatus and Method for Producing a Data Carrier”; toavoid repetition, this referenced application is made the subject matterof the present application.

The pin 1 has an upwardly open hollow chamber 5, which is delimited tothe side by a side wall 7, and toward the bottom by a base 8 of the pin1. The outer periphery of the wall 7 is adapted to the shape of theinner or central holes of the substrates 2,3 and in particular in alower region the pin is provided with a precisely ground outer peripheryin order to ensure a good centering and guidance of the two substrates2,3 relative to one another. The upper end of the wall is beveled, sothat it defines an upwardly tapering inclined surface 9. The inclinedsurface 9 enables a centering and guidance of the substrates when theyare received on the pin.

Disposed on the side wall 7 of the pin 1 is a plurality of projectionsor noses 10, two of which are illustrated in FIGS. 1 to 3. With thepresently preferred embodiment, four noses 10 are provided. The noses 10are pivotably disposed on the wall 7 of the pin 1 in a suitable mannerin order to be pivotable between the positions shown in FIGS. 1 and 2.

By means of compression springs 12, the noses 10 are biased radiallyoutwardly away from the pin 1 into the position shown in FIG. 1, as willbe described in greater detail subsequently. Provided in the hollowchamber 5 of the pin 1 is a conical or tapered element 3 that tapersupwardly. The tapered element 13 is disposed within the hollow chamber 5such that it is vertically movable and is biased upwardly via a spring15 into the position-shown in FIG. 1. One end of the compression springs12 is supported against the tapered element 13, and the other end of thecompression springs is supported against the noses 10 in order to pressthem outwardly. In so doing, the springs 12 can glide along the conicalsurface of the tapered element 13, as a result of which the outwardlydirected biasing force is altered.

A non-illustrated spring ring or lock washer extends about the lowerends of the noses in order to draw them to the pin 1 into the positionshown in FIG. 1. In so doing, the spring constant of the spring ring isso low that it is does not exceed the outwardly directed biasing forceexerted by the compression springs 12 as long as the tapered element 13,and hence the inner support of the springs 12, are in the position shownin FIG. 1. If, as shown in FIG. 2, the tapered element 13 is presseddownwardly by a rod 17, the springs 12 glide along the conical surfaceof the tapered element 13, as a result of which the outwardly directedbiasing force of the springs 12 is reduced. In this position, the springconstant of the spring ring is sufficient to draw the noses 10 to thepin 1 into the position shown in FIG. 2.

During the movement of the noses 10 between the position shown in FIG. 1and the position shown in FIG. 2, the substrate 2 glides along the outersurfaces of the noses 10 in the direction of the substrate 3. In sodoing, the linear surfaces of the noses 10 provide a good guidance ofthe substrate 2 which prevents a tilting or cocking of the substrate.This guidance is maintained during an essentially constant transmissionof force until the substrate 2 rests upon the substrate 3.

The rod 17 can be part of a non-illustrated pressure ram that serves forpressing the substrates 2,3 together.

Instead of the above-described arrangement of compression springs 12 forpressing the noses 10 outwardly, and a non-illustrated spring ring fordrawing the noses together, it would also be possible for the noses 10to contact the tapered element 13 directly and to be pressed outwardlyby the tapered element 13 in the position shown in FIG. 1. If thetapered element 13 is moved into the position shown in FIG. 2, the nosesglide along the conical outer surface of the tapered element 13 and aredrawn into the position shown in FIG. 2 by the non-illustrated springring. The same effect could also be achieved if the springs 12 shown inFIG. 1 were to be embodied as tension springs.

FIG. 3 shows a substrate handling apparatus 20 for the removal of thejoined-together substrates 2,3 from the pin 1. The handling apparatus 20is provided with a spacer rod 22 for pressing the tapered element 13down in order, prior to the removal, to move the noses 10 into theirretracted position of FIG. 3. The handling apparatus 20 is furthermoreprovided with vacuum fingers 24, two of which are illustrated in FIG. 3,by means of which the substrates 2,3 are drawn against the handlingapparatus 20 and held thereon. The vacuum fingers 24 are displaceable inheight relative to the main body 25 of the handling apparatus 20, forexample by means of a bellows mechanism, in order to enable a relativemovement, in terms of height, between the spacer rod 22 and the vacuumfingers 24.

A specific embodiment of the invention will be described subsequentlywith the aid of FIGS. 4 to 7, whereby the same reference numerals areused as in FIGS. 1 to 3 to the extent that they relate to the same orsimilar parts.

FIG. 4 shows a processing station 30 for the joining together ofsubstrates 2,3 to form a DVD. The processing station 30 has a supportmember 32 as well as a processing chamber 34. The support member isessentially formed by a main body 36 that defines a support for thesubstrate 3. As can be best seen in FIG. 7, the main body 36 has anupwardly directed surface 38 that, in a portion located below thesubstrate, is provided with a recess 39 in order when the substrate isplaced on to form a chamber 40 between the substrate 3 and the main body36. The chamber 40 is supplied with a pressurized fluid via lines 41, 42in order during a joining process to exert an upwardly directed pressureagainst the substrate. By means of O-rings 45,46 disposed in the surface38, the chamber is sealed off toward the outside, so that during thejoining process, no fluid can escape from the chamber.

Formed in the central portion of the surface 38 is a further recess 47in which a centering and holding pin 50 is accommodated. The pin 50 isprovided with projections or noses 51 that are pivotably mounted thereonand that have linear outer surfaces 53. The pin 1 is provided with ashaft or extension 55 that is disposed radially inwardly relative to thenoses 51; the extension extends from below between the noses 51 and inparticular to the height of the pivotable attachment of the noses.Disposed between the noses and the extension are compression springs 56that press the noses 51 radially outwardly. In so doing, the noses 51form a conical shape that widens in a downward direction and upon whicha substrate 2 can be placed. By means of the springs 56, the noses arepressed outwardly with an adequate force in order to hold the substrate2 in the position shown in FIG. 4. In order to join the substrates 2,3together, a pressure is applied to the substrate 2 from above by meansof an apparatus that will be described subsequently; this pressure issufficient to overcome the spring force and to effect an inward pivotingof the noses 51. In so doing, the substrate 2 glides along the linearouter surfaces 53 of the noses 51 and is precisely guided during thegliding movement, thereby preventing a tilting or cocking of thesubstrate 2. The substrate 2 is essentially guided until it comes intocontact with the substrate 3 and is pressed together therewith.

The processing chamber member 34 has a housing 60 that defines adownwardly open chamber 62. The housing 60 and the support member 32 aremovable relative to one another, whereby the housing can be positionedupon the surface 38 of the support member 32 in order to close off theunderside of the chamber 62 in the housing 60. The chamber 62 can bevented via a line 64, so that a joining together process of thesubstrates 2,3 in the vacuum can be effected.

Disposed in the chamber 62 is a movable press or ram 65 that in adownwardly directed surface 67 is provided with a recess 68 in order toform a chamber 70 between the ram 60 and the substrate 2 when the ram 60is moved into contact with the substrate 2 as shown in FIG. 6. Thechamber 70 is sealed off toward the outside and toward the inside byO-rings. In the same manner as the chamber 40, the chamber 70 can besupplied with a fluid in order during a joining process to press thesubstrate 2 downwardly against the substrate 3. Pressing the substratestogether by means of a fluid introduced into the chambers 40,70 providesa uniform surface pressure against the substrates and thus ensures agood joining process.

A joining together of the substrates will now be explained with the aidof FIGS. 4 to 6. As can be seen from FIG. 4, a first substrate 3 isplaced upon the surface 38 of the support member 32, and a secondsubstrate is placed upon the noses 51 of the pin 50, as a result ofwhich a defined spacing is maintained between the substrates. Thehousing 60 of the processing chamber member 34 is spaced from thesurface 38 of the support member 32.

As shown in FIG. 5, the housing 60 is subsequently positioned upon thesurface 38 in order to form a closed processing chamber 62. Theprocessing chamber is now vented via the line 64 in order to carry outthe subsequent joining together of the substrates under vacuumconditions. This prevents air pockets or bubbles between the substratesduring the joining together.

The ram 65 is lowered until it comes into contact with the substrate 2,and the substrate 2 is then pressed downwardly by the ram 65, which islowered further. In so doing, the edges of the inner hole of thesubstrate 2 are guided by the inwardly pivoting noses 51, therebypreventing a tilting of the substrate 2.

As soon as the substrate 2 has been lowered to such an extent that itcomes into contact with the substrate 3, in particular with an adhesivelayer disposed thereon, as shown in FIG. 6, a pressurized fluid isintroduced into the chambers 40,70 in order to press the substrates 2,3together in a controlled manner.

Instead of the joining together apparatus 30 described above, it is tobe understood that another suitable apparatus can also be used inconjunction with the centering and holding pin. One example for anotherapparatus is described in the patent application that belongs to thesame applicant and was filed on the same day and has the title“Apparatus and Method for Producing a Data Carrier”, with thisapplication being made the subject matter of the present application inorder to avoid repetition.

FIG. 7 shows a support member 32 of a processing station 30 pursuant toFIGS. 4 to 7, whereby in addition an actuating element 74 is shown thatis suitable for pivoting the noses 51 of the pin 50. The actuatingelement 74 is provided with a shaft 76, as well as with a conical ortapered element 78 secured thereon. The shaft 76 and the tapered element78 can, of course, also be embodied as a single part. The taperedelement 78 is provided with downwardly tapering surfaces 79 that can beintroduced between the noses 51 of the pin 50, as indicated in FIG. 7.When the tapered element is introduced between the noses 51, it comesinto contact with rounded end portions 80 of the noses 51 and pressesthese noses apart during a further downwardly directed movement of thetapered element 78. As a result, the noses, especially the linear outersurfaces 53, are pressed inwardly in the direction of the pin 50 againstthe outwardly directed bias of the springs 56. The tapered element canpivot the noses entirely inwardly in order to enable a movement of thesubstrates along the pin 50.

The actuating element 74 is, for example, associated with the ram 65 ofFIGS. 4 to 6 in order to enable a controlled placement of the substrate2. However, the actuating element 74 can also be associated with asubstrate removal unit in order to permit a free removal of thesubstrates 2,3 from the pin 50 after the joining together.

The invention has been described with the aid of preferred specificembodiments of the invention, without, however, being limited thereto.In particular, the apparatus is usable not only for joining substratestogether to form DVD's. The invention can also be used with an apparatusfor coating or layering an optical carrier, as described, for example,in the patent application of this applicant that was filed on the sameday as the present application and has the title “Apparatus and Methodfor Coating an Optically Readable Data Carrier”. To avoid repetition,this other application is made the subject matter of the presentapplication. Furthermore, the apparatus is also not limited to thejoining together of two substrates. Rather, a plurality of substratescan also be joined together sequentially or also essentiallysimultaneously.

The specification incorporates by reference the disclosure of Germanpriority document 199 27 514.9 filed 16 Jun. 1999 and Internationalpriority document PCT/EP00/05440 of Jun. 14, 2000.

The present invention is, of course, in no way restricted to thespecific disclosure of the specification and drawings, but alsoencompasses any modifications within the scope of the appended claims.

What is claimed is:
 1. An apparatus for joining together at least twosubstrates, each of which has an inner hole, said apparatus comprising:a pin that is adapted to said inner holes of said substrates, whereinsaid pin is provided with at least two noses that are movable radiallyrelative to said pin, and wherein said at least two noses have linearouter surfaces upon which edges of said inner holes of said substratescan glide downwardly during movement of said noses toward said pin, andwherein said noses guide the downward movement of the substrates.
 2. Anapparatus according to claim 1, wherein said at least two noses keepsaid substrates spaced apart prior to a joining together process.
 3. Anapparatus according to claim 1, wherein said pin is a centering pin. 4.An apparatus according to claim 3, wherein said at least two noses arepivotably mounted on said centering pin.
 5. An apparatus according toclaim 1, wherein at least one biasing unit is provided for an outwardbiasing of said at least two noses.
 6. An apparatus according to claim5, wherein said biasing unit is provided with at least one spring.
 7. Anapparatus according to claim 5, wherein means are provided for varyingsaid biasing of said at least two noses.
 8. An apparatus according toclaim 5, wherein a tensioning element is provided for drawing said atleast two noses inwardly, and wherein said tensioning element has atensioning force that is not sufficient to overcome a normally outwardlydirected biasing force of said at least two noses.
 9. An apparatusaccording to claim 8, wherein when said outwardly directed biasing forceof said at least two noses is reduced, said tensioning force of saidtensioning element draws said at least two noses inwardly.
 10. Anapparatus according to claim 8, wherein said tensioning element is aspring ring that is disposed on said at least two noses.
 11. Anapparatus according to claim 10, wherein said spring ring is disposed onan inner periphery of said at least two noses.
 12. An apparatusaccording to claim 1, wherein means are provided for exerting pressureupon said substrates for effecting movement of said at least two nosestoward said pin.
 13. An apparatus according to claim 1, wherein anactuating element is provided for radially moving said at least twonoses.
 14. An apparatus according to claim 13, wherein said actuatingelement is insertable between said at least two noses.
 15. An apparatusaccording to claim 13, wherein said actuating element has a conicalconfiguration.
 16. An apparatus according to claim 13, wherein ends ofsaid at least two noses that face said actuating element are roundedoff.
 17. An apparatus according to claim 1, wherein said at least twonoses are embodied as lever arms.
 18. An apparatus according to claim 1,wherein a tapered element is disposed in said pin, and wherein saidtapered element is movable counter to a biasing means.
 19. An apparatusaccording to claim 18, wherein said biasing means is a spring.
 20. Anapparatus according to claim 18, wherein a biasing element is disposedbetween said tapered element and said at least two noses.
 21. Anapparatus according to claim 18, wherein an outwardly directed biasingof said at least two noses is variable via a movement of said taperedelement.
 22. An apparatus according to claim 1, wherein four noses areprovided.
 23. An apparatus for joining together at least two substrates,each of which has an inner hole, said apparatus comprising: a pin havingan outer diameter less than said inner holes of said substrates suchthat each of said substrates can freely pass over said pin uponinsertion of said substrate onto said pin; and at least two noses, eachnose being movable relative to said pin and having an outer surface forsliding engagement therealong of an inner hole edge location of arespective one of said substrates being inserted over said pin, eachnose moving radially inwardly as it yieldably resists the downwardsliding movement of the respective engaged inner hole edge location ofsaid respective one substrate as said respective one substrate is beinginserted over said pin, wherein the downward sliding movement of saidrespective one substrate along said noses is controlled by the inwardmovement of said noses relative to said pin and the yielding resistanceof each of said noses relative to the other of said noses is such thatsaid respective one substrate remains substantially centered on said pinas said respective one substrate slides along said noses, and the axiallower limits of said outer surfaces of said noses are axially above alower extent of said pin having a length sufficient for said respectiveone of said substrates to move downwardly beyond said noses into aposition on top of an already fully inserted substrate disposedtherebelow; and means for biasing said noses radially outwardly fromsaid pin such that said noses immediately engage said respective onesubstrate as said one respective substrate moves downwardly along saidpin.